The present invention is an improved magnetic head suspension assembly (HSA) for use with dynamic magnetic storage devices or rigid disk drives. More exactly, it is a head suspension assembly that has a one-piece structure constructed with a load beam and a flexure region. Specifically, this invention describes improvements in the construction of the flexure region to improve dynamic performance of the HSA, decrease pitch and roll stiffnesses, increase lateral and in plane stiffnesses, improve manufacturability, and improve head bond location.
Conventionally available magnetic head suspension assemblies for rigid disk drives allow magnetic read/write heads to pitch about a first or transverse axis and roll about a second or longitudinal axis, orthogonal to the first axis, when imperfections in the disk drive assembly tend to place the heads in improper positions relative to the associated disk surface. The present invention allows significant reductions in the pitch and roll stiffness of the head suspension assembly, thus allowing the heads to easily maintain proper attitude to the disk. At the same time, the present invention increases stiffness in the direction of rotation of the disk to maintain proper head position with respect to the suspension assembly. Further, the invention resists permanent distortion to the HSA which can be caused by forces in all directions.
Conventional head suspension assemblies consist of a support baseplate, load beam, and flexure, which are usually separately etched, stamped and then welded together. According to the present invention, the flexure is constructed as an integral part of the load beam, which reduces manufacturing steps and improves the ability to manufacture the HSA with the proper head position and attitude.
Conventional head suspension attachments or base plates are welded to the load beam and attached to an actuator arm and are generally configured for swage or screw attachment means. As described in commonly assigned U.S. Pat. No. 5,198,945, issued Mar. 30, 1993, the attachment means is an integral part of the load beam. This method of attachment avoids welding, thus reducing process steps, easing disk drive assembly, and improving the ability to position the head properly with respect to the actuator arm. The load beam attaches to the actuator arm by an attachment means employing an interference fit, such as a clip.
As also described in U.S. Pat. No. 5,198,945, the load beam can be attached to the actuator arm by a shrink fit interference means encircling the arm and load beam(s). Such a shrink fit can be performed by heating the shrink fit interference means to expand and then contract around the actuator arm and load beam(s), or by heating the shrink fit interference means to simply contract around the actuator arm and load beam(s). This method of attachment reduces the number of components and process steps, and allows the HSA to be attached to and removed from the actuator arm easily.
Conventional means for positioning and aligning the read/write head to the suspension assembly, when attaching the head suspension assembly to the actuator arm, is to place an alignment pin through a hole in the load beam, another alignment pin through a hole(s) in the baseplate, and mount the baseplate and the actuator arm with screws or with the baseplate boss. As also described in U.S. Pat. No. 5,198,945, an alignment pin is positioned through a hole in the load beam and another alignment pin is positioned through a slot at the base end to improve the accuracy and ease of positioning the head with respect to the suspension assembly and to facilitate the alignment of the head suspension assembly with respect to the actuator arm. As can be readily understood, this arrangement may equally well be reversed, with a hole positioned in the base end and a slot positioned in the load beam. The pin/hole registration will keep the parts aligned in the x and y directions, while the pin/slot registration keeps the parts from rotating about the z axis. Further, a single one-piece suspension structure constructed with both a load beam region and a flexure region eliminates the tolerance build up from welding three separate components together and allows the head location to depend solely on the precision manufacture of the holes and slots.
Conventionally available magnetic head suspension assemblies have load beams with rails extending either away from the rigid disk or toward the rigid disk, as shown in commonly assigned co-pending application Ser. No. 08/050,517, filed Apr. 20, 1993, which in turn is a continuation of Ser. No. 07/583,048, filed Sep. 14, 1990, now abandoned.
In the prior art, the rail oriented to project from the surface of the load beam, away from the associated disk surface, offered increased clearance between the disk and the load beam for lifting the load beam, while the rail oriented toward the disk surface offered increased clearance between two back to back head suspension assemblies and allowed for closer disk spacing. The present construction offers increased clearance on both sides of the head suspension assembly for lifting the load beam and for allowing closer disk spacing. U.S. Pat. No. 5,198,945 uses a rail form line that is not parallel to the disk surface over its entire length but is closer to the disk at the slider end and withdrawn from the disk at the base end, such that the lift clearance can be maximized near the base plate and the disk spacing clearance can be maximized near the slider.
According to the present invention, a magnetic head suspension, for supporting a magnetic head at a fixed distance from a rigid actuator arm, has a single one-piece structure having a flexure region and a load beam region. In the single one-piece structure, a proximal end of the load beam region is joined to the rigid actuator arm, and the flexure region projects distally beyond the load beam region. The flexure region is divided into a planar head support region, and a set of at least two flexible arms, defined by a first set of slots in a surface of the flexure region. The head support region is constructed and arranged for receiving a head slider to be bonded thereto. The slots which define the set of at least two flexible arms also define a perimeter of the head support region. Each of the arms generally enclose at least a part of a perimeter of the head support region. The arms are constructed and arranged for flexible suspension of the head support region by formed offsets, which position a plane of the head support region recessed from a plane of the load beam region. The slot patterns together with the offsets can be referred to as an arrangement of offset forms.
Also according to this invention, a magnetic head suspension, for supporting a magnetic head at a fixed distance from a rigid actuator arm, has a single one-piece structure having a flexure region and a load beam region. A proximal end of the load beam region is joined to the rigid actuator arm. The flexure region projects distally beyond the load beam region. The flexure region is divided into a head support region, a first set of flexible arms, defined by a first set of slots in a surface of the flexure region, and a second set of flexible arms, defined by a second set of slots in a surface of the flexure region. The flexure region is constructed and arranged for receiving a head slider to be bonded thereto. The first set of slots, which defines the first set of flexible arms, also defines a perimeter of the head support region. Each of the first set of arms generally encloses at least a part of the perimeter of the head support region. The slots of at least one of the flexible arms are generally arcuate. The second set of flexible arms is defined by a second set of slots in the surface of the flexure region. The second set of slots also defines a perimeter of the first set of arms. The second set of arms is constructed and arranged with formed offsets, which position a plane of the head support region recessed from a plane of the load beam region.
Further, according to the present invention, a magnetic head suspension for supporting a magnetic head at a fixed distance from a rigid actuator arm, has a single one-piece element having a flexure region and a load beam region. In the one-piece element, a proximal end of the load beam region is joined to the rigid actuator arm, and the flexure region projects beyond the load beam region. The flexure region is divided into a head support region for receiving a disk drive head to be bonded thereto. A first set of slots in the flexure region is around substantially the entire perimeter of the head support region, with exception of a first set of two support pivot points aligned on opposite sides of the head support region, to define a first set of flexible arms for supporting the head support region for gimballed movement about a first rotational axis. A second pair of slots in the flexure portion is around substantially the entire perimeter of the first set of arms, with exception of a second set of two support pivot points aligned on opposite sides of the head support region, to define a second set of flexible arms for supporting the head support region for gimballed movement about a second rotational axis of the head support region, which is angularly spaced from the first rotational axis. The second set of flexible arms are constructed and arranged with formed offsets, which position a plane of the head support region and the first set of arms recessed from a plane of the second set of arms and the load beam region.
Also, according to this invention, a magnetic head suspension for supporting a magnetic head at a fixed distance from a rigid actuator arm, has a single one-piece structure having a flexure region and a load beam region. The structure comprises a proximal end of the load beam region joined to the rigid actuator arm and the flexure region projecting distally beyond the load beam region. The flexure region is divided into a head support region for receiving a disk drive head slider to be bonded thereto, a first set of slots in the flexure region to define a first set of flexible arms, and a second set of slots in the flexure region around substantially the entire perimeter of the first set of arms, to define a second set of flexible arms. Each arm of the first set of flexible arms terminates at either arm end in equally spaced first intersection points about a perimeter of the head support region, for suspending the head support region for gimballed movement relative to the load beam region. The flexible arms are generally curved. The second set of slots in the flexure region is around substantially the entire perimeter of the first set of arms, to define a second set of flexible arms, each of which terminates at either end to equally spaced second intersection points about a perimeter of the first set of arms, for suspending the first set of arms for gimballed movement relative to the load beam region. The first intersection points lie on a first axis of the suspension, and the second intersection points lie on a second axis of the suspension, radially spaced from the first axis of the suspension. The second set of flexible arms are constructed and arranged with formed offsets, which recess a plane of the head support region and the first set of arms from a plane of the second set of arms and the load beam region.
By constructing the load beam and flexure as a single one-piece structure, the accuracy of orientation of the flexure in relation to the load beam is carefully controlled and the overall construction is optimized to improve its dynamic characteristics and greatly reduce its size.
It is an object of the present invention to provide an improved magnetic head suspension having a single one-piece structure with a load beam region and a flexure region.
It is also an object of the present invention to provide a flexure having reduced flexure pitch and roll stiffness and increased lateral or rotary stiffness. High lateral stiffness serves two purposes. One purpose is to provide a spring to counteract lateral accelerations at the head. The lateral accelerations may result from, but are not limited to, such events as the head coming to a crash stop during a seek, or a drive subjected to external accelerations, such as those found in portable applications. Assuming the lateral forces generated are below the design limits, a one-piece structure having both a flexure region and a load beam region, as described for the present invention, will return the head to its original position.
Traditional dimple/load beam interfaces, that is, a Watrous style flexure constructed separately from and attached to a load beam, will not return the head to its original position. The difference is that with the one-piece structure having both a flexure region and a load beam region, according to the present invention, the head is positioned relative to the load beam with a set of linear xe2x80x9cspringsxe2x80x9d. Dimple/load beam interfaces of the prior art use linear springs in combination with non-linear frictional effects to provide positioning of the head. The result is that, when the head is subjected to high lateral accelerations, the relatively low lateral stiffness of the flexure of the prior art will not return the head completely. The head will be offset from the desired location by the distance where the lateral stiffness equals the dynamic friction at the dimple/load beam interface.
A further object of the present invention is to provide a load beam with increased clearance between itself and the rigid disk, increased clearance on the opposing side of the load beam to reduce disk spacing or total rigid disk drive spacing, improved resonance, and lowered spring rate.
These and other objects of the present invention will be apparent with reference to the drawings, the description of the preferred embodiment, and the claims.